Q: I’m a sophomore in high school. My number one concern is whether or not I’m officer material and can lead Marines. I don’t know if I can hold up to the leadership standards the Marines require.
A: That’s a big question. Since you are starting this process so early, I would say the answer to that question is entirely up to you. If you want to be a leader of Marines, you have the time to develop yourself as such. Seek new leadership opportunities and get outside of your comfort zone on a regular basis.

If I was back in your shoes, I would consider enlisting in the reserves when you graduate. I want to emphasize that this option is not for everyone. But, doing so will give you the opportunity to view Marine officers in action and determine whether or not you want the same for yourself.
Remember, that even a Lance Corporal is a leader of Marines.
How do I know if I can lead Marines?
Seek out past and present Marine officers and ask them about their experience. Then, compare it against the experiences of other service members. There is more to the world than the Corps.

Regarding OCS, OCS screens for desire to lead and potential to lead. The fact that you found the blog shows you are proactive and take the initiative.
I know a candidate who would have been a great officer. But, he denied his commission after completing PLC Juniors and Seniors. Even having “made it”, this may not be right for you.
I’ll leave you with this. Before I joined, my pastor, a retired Navy Chaplain who spent his career with the Marines, told me “Joining the military is like getting married. You don’t really know what it is like until you do it.”
Ultimately, it’s upon you to do the due diligence and research this option to decide if you can lead Marines.